Surgical endoscopy is a surgical technique of using small-diameter long-handled tools such as graspers, forceps, scissors, retractors, dissectors and clamps specially designed to be inserted through small incisions in the skin (or other openings in the body) to perform operations within the body. The surgeon performing the surgery often cannot see the operation directly, and must watch the procedure on a video monitor fed by an endoscopic camera or endoscope. Endoscopic surgery replaces open surgery, which requires large incisions, essentially opening the body cavity completely, in order to perform surgery deep within the body. Endoscopic techniques have been used for gall stone removal, gall bladder removal, hernia repair, tumor removal, lymph node removal and appendectomy and many other operations. Endoscopic surgery is also called laparoscopic surgery, video assisted surgery, minimally invasive surgery, and band-aid surgery, but throughout this specification the term endoscopic surgery or laparoscopic surgery will be used.
To illustrate the background of the inventions described below, the example of the laparoscopic cholecystectomy, hernia repair or lymphadenectomy, as well as the operation for harvesting a blood vessel, will be used to illustrate both the old laparoscopic procedures and the new laparoscopic procedures now possible with the new devices. In the old procedure, a working space was created in the abdomen using the process called pneumoperitoneum or insufflation. Insufflation is the process of injecting gas into the body to blow it up like a balloon, creating a chamber filled with gas. When performed on the abdomen, the peritoneum is inflated and the procedure is known as pnuemoperitoneum. The procedure can be used for inflating a space between the peritoneum and the skin to permit laparoscopic hernia repair, as illustrated in U.S. Pat. No, 5,496,345 issued to Keiturakis et al. and entitled "An Expansible Tunneling Apparatus for Creating An Anatomic Working Space." Insufflation can be used also to inflate a tunnel shaped working space over a blood vessel, to facilitate blood vessel harvesting, as described in U.S. patent application Ser. No. 08/267,484 entitled "Extraluminal Balloon Dissection Apparatus and Method". incorporated herein by reference. While the chamber is filled with gas, the surgeon inserts long slender laparoscopic tools through trocars and cannulas which pierce the skin and provide access ports into the insufflated chamber.
For abdominal surgery such as a cholecystectomy (gall bladder removal), the insufflation is accomplished by the following procedure. An incision is made at the lower edge of the belly button or umbilicus. The surgeon uses his fingers or a blunt dissection tool such as a blunt nosed obturator to uncover the fascia or abdominal muscles, then a large needle, referred to as a Verres needle is inserted into the abdomen or peritoneal cavity. The verres needle punctures the fascia and peritoneum which cover the abdomen. A pressurized gas such as CO.sub.2 is injected into the abdomen through the needle, in effect inflating the abdomen like a balloon. After the abdomen is inflated, the Verres needle is removed. After the needle is removed, trocars and cannulas are inserted into the space created by the insufflation. Endoscopic instruments including an endoscope or laparoscope, scissors, graspers, etc., are inserted into the abdomen through the cannulas and manipulated to dissect tissue surrounding the gall bladder, remove the gall bladder, and stitch the internal wounds.
To harvest the saphenous vein using laparoscopic procedures, the surgeon may insufflate a tunnel shaped work space over a blood vessel. The tunnel is first created using obturators or tunneling devices or balloons inserted through small incisions along or over the saphenous vein. After the tunnel is created, the surgeon may insert skin seals and cannulas, and insufflation gas is injected through one of the trocars. While the tunnel is insufflated, the cannulas permit the surgeon to insert laparoscopic instruments into the tunnel to perform surgery on the saphenous vein.
The cannula used in the procedures described above is a length of rigid tube. The trocars and cannula are designed to allow laparoscopic instruments to pass through them and prevent gas from escaping the abdomen or other insufflated work space. The cannula may have a flapper valve or a trumpet valve inside which opens to allow an endoscope or laparoscopic or other instrument to pass through, and valve closes when the laparoscope is removed. Some trocar/cannula devices also contain a duckbill valve to assist in sealing the trocar. The cannulas are typically about 6 inches or 15 centimeters long, and come in diameters matching various laparoscopic devices, generally from 2 to 15 mm.
Some surgeons use bare cannulas, secured only by a tight fit with the skin and fascia. However, cannulas frequently slip out of the body during use, disrupting the procedure and possibly endangering the patient. To prevent this danger, surgeons have devised a variety of methods to secure the cannula to the body and prevent it from slipping out of the body. Some cannulas are provided with threaded sleeves, fixed to the cannula. Some cannulas are provided with a threaded gripper with a smooth inner bore that matches the size of the cannula, so that the cannula can slide inside the gripper as shown in FIG. 2. The gripper stabilizes the cannula so that it will not slip out of the body inadvertently, but can be easily slipped out when the surgeon wants. The threaded gripper is simply screwed into the incision in the skin. This option permits the ready insertion and removal of smooth walled cannulas by sliding them in and out of the gripper. Other grippers have been used, such as the gripper with expandable arms, the gripper with inflatable balloon on the outside, and the Hasson cannula. These devices are illustrated in Oshinsky, et al., Laparoscopic Entry and Exit, reprinted in Urologic Laparoscopy at 91-101 (Das & Crawford ed. 1994). These devices are variously referred to as threaded skin seals, screw skin seals, skin anchors, obturators, grippers, trocar stabilizers or cannula stabilizers.
The surgeon usually needs to place several trocars and cannulas into the abdomen, and inserts as many as needed to accomplish the intended operation. The first cannula placed through the belly button is used to insert a laparoscope so that the placement of other trocars and cannulas can be viewed from inside the abdomen. After several cannulas are in place, the surgeon can view the procedure through any port, and can insert laparoscopic scissors, cutters and graspers and other tools through the cannulas in order to perform the surgery. The typical endoscopic graspers 3 used for stitching inside the abdomen are shown, deployed inside the cannulas, in FIG. 2. A bare cannula 4 is used with endoscopic graspers 3a. Another pair of laparoscopic graspers 3b is inserted into a cannula 4a which is inserted through a threaded gripper 5. A third cannula 6, shown with a threaded outer surface, is provided for an endoscope 34 which is inserted into the work space to provide the surgeon with a video view of the graspers and body tissue.
The arrangement of the cannulas and trocars is required because the abdomen must be inflated to make room for the surgeon to work. The small diameter of the cannulas keeps the incisions small, and the matching diameter of the laparoscopic instruments is necessary to prevent leakage of the insufflation gas from the abdomen. Laparoscopic instruments of various designs are available, and they generally are about 5 to 12 mm in diameter (to match the inside bore of the cannulas) and about 10 to 40 cm in length. They are long and therefore difficult to use, and they are usually used when the surgeon can see them only through the laparoscope. Modern laparoscopic procedures require the surgeon to view the procedure on a video monitor. It may take a surgeon a lot of practice before becoming comfortable and skillful with the laparoscopic graspers, grippers and scissors. These tools are more difficult to use than the surgical tools which every surgeon uses in normal surgery, such as those shown in FIG. 3, in use during open laparotomy. The normal graspers are shown in use while the surgeon is tying off a suture. This normal procedure is familiar to a large number of surgeons. The normal surgical graspers 7a and 7b are shown in use in FIG. 3, suturing body tissue 8 with suture 9, and it can readily be appreciated that the laparoscopic graspers shown in FIG. 2 require significantly more skill than the normal surgical tools. One of the drawbacks of the known cannulas and grippers is that they are adapted to admit only relatively narrow instruments, and are therefore generally unsuited for use with ordinary open-incision surgical tools.
It would be advantageous to use normal surgical tools during laparoscopic procedures, but this is usually not permitted by the typical construction of the trocars and cannulas which are too narrow, long and rigid to permit passage of the normal surgical tools. Most surgeons are very well trained in using conventional non-endoscopic instruments, such as the open-incision graspers shown in FIG. 3, and numerous procedures involving the graspers such as tying off a suture are well known and well practiced. The endoscopic instruments shown in FIG. 2, on the other hand, are not well known and well practiced, and generally require significantly more skill than the more familiar open-incision instruments. Thus, there is a need to provide cannulas and grippers which would accommodate the instruments used in open-incision procedures.